1. Field of the Invention
The present invention relates to a technology for controlling a remote camera and a network camera used for video conferencing, and real-time remote schooling.
2. Background
Japanese Patent Application Publication (JPAP) No. 07-274150 discloses a monitoring system. When an operator at a distant place specifies with a pointing device a range a screen which the operator wants to zoom in, the system calculates the view angle of a camera lens and the direction of the camera. The calculated information is sent to a camera controller for controlling the camera
JPAP No. 2003-134382 describes that a still image from a remote-controlled video camera is displayed on a screen of a monitor at the same time as a moving image from the video camera. The video camera is controlled by specifying a position on the still image with a mouse so that the specified position is located at the center of the moving image. The video camera is controlled by operating with a mouse a pan control cursor, a tilt control cursor, and a zoom control cursor, which are displayed on the screen of the monitor.
The camera-to-subject distance changes when the direction of the camera is changed in order to shoot a different subject, resulting in a different shooting range. That is, shooting screen range (shooting range) changes. In order to keep the same shooting range, zoom adjustment is required after the direction of the camera is changed. Focus adjustment may be carried out by visual observation by the operator, or by calculation based on measurement of the camera-to-subject distance using a distance measuring function installed in the camera.
However, because the above-described technique takes time, some time is required before the camera is directed to a subject to be photographed, and a desired shooting range is established. Accordingly, there is a need for a technology for controlling a remote camera that can rapidly establish a desired shooting range as the direction of a camera is changed.